Simultaneous particulate design of primary and agglomerated crystals of steroid by spherical agglomeration in liquid for dry powder inhalation

An expert opinion on respiratory delivery of high dose powders for lung infections

INTRODUCTION

High dose powder inhalation is evolving as an important approach to to treat lung infections. It is important to its identify applications, consider the factors affecting high dose powder delivery, and assess the effect of high dose drugs in patients.

AREA COVERED

Both current and pipeline high dose inhalers and their applications have been summarized. Challenges and opportunities to high dose delivery have been highlighted after reviewing formulation techniques in the context of factors affecting aerosolization, devices, and patient factors.

EXPERT OPINION

High dose inhaled delivery of antimicrobials is an innovative way to increase treatment efficacy of respiratory infections, tackle drug resistance, and the scarcity of new antimicrobials. The high dose inhaled technology also has potential for systemic action; however, innovations in formulation strategies and devices are required to realize its full potential. Advances in formulation strategies include the use of excipients or the engineering of particles to decrease the cohesive property of microparticles and their packing density. Similarly, selection of a synergistic drug instead of an excipient can be considered to increase aerosolization and stability. Device development focused on improving dispersion and loading capacity is also important, and modification of existing devices for high dose delivery can also be considered.

Evaluation of the effect of some additives on the efficiency of binder liquid in wet agglomeration of crystals

OBJECTIVE

Wet agglomeration is a process wherein dispersed particles are held together in an aggregated form by the presence of a small quantity of solvent which acts as binder liquid. In this work, the efficiency of binder liquid was tested in the presence of various additives.

METHODS

Solid state of carbamazepine (CBZ) agglomerates was characterized by DSC and FT-IR. The obtained agglomerates were also investigated in terms of yield, size distribution, friability, and drug release.

RESULTS

CBZ agglomerates formed only in the presence of talc, span, and croscarmellose sodium (CCS), whereas ethyl cellulose and eudragit RS100 failed to make CBZ agglomerates. The presence of talc decreased the agglomerate size and produced CBZ agglomerates with a poor strength. However, span and CCS led to larger agglomerates with superior strength. In contrast to CCS samples, span and talc altered the dissolution rate of CBZ. FT-IR results showed that there is an interaction between CCS and drug.

CONCLUSION

This study suggests that care must be taken when additives are used to manufacture agglomerates as the type of additives even in low concentrations can have a big impact on the efficiency of the binder liquid in forming agglomerates thereby affecting the quality of agglomerates.

Agglomerative crystallization of ABT‐510 in a partially miscible solvent system

A modification of wet agglomeration technique is developed and demonstrated by agglomerative crystallization process for a nonapeptide (ABT-510) to improve processing of needle like crystals. Our procedure involves exploiting partial miscibility of the crystallization solvent system for in situ generation of a wetting agent with suitable agglomerative properties. Experiences with ABT-510 show that a relatively small fraction of phase separation (1-5%) is needed to create enough wetting agent for effective agglomeration. Manipulations in the properties and quantity of the wetting agent easily achieved by modifying process trajectories in the solvent space lead to significant variations in agglomerative particle shapes. An optimal process trajectory is established by thorough evaluation of solid-liquid equilibria, liquid-liquid equilibria, properties of the wetting agent and agglomerative particle shape. Optimum antisolvent addition profile is also established and the process scaled up using suitable process analytical tools (PAT) to monitor for consistent performance. This optimally designed agglomerative crystallization process consistently lead to agglomeration of the particles just inside the biphasic solvent region. Extremely rapid crystal form conversion to the desired crystalline form is also observed in the vicinity of the biphasic solvent region, probably as a consequence of density fluctuations generated by the onset of solvent immiscibility.

Particle Engineering for Pulmonary Drug Delivery

With the rapidly growing popularity and sophistication of inhalation therapy, there is an increasing demand for tailor-made inhalable drug particles capable of affording the most efficient delivery to the lungs and the most optimal therapeutic outcomes. To cope with this formulation demand, a wide variety of novel particle technologies have emerged over the past decade. The present review is intended to provide a critical account of the current goals and technologies of particle engineering for the development of pulmonary drug delivery systems. These technologies cover traditional micronization and powder blending, controlled solvent crystallization, spray drying, spray freeze drying, particle formation from liquid dispersion systems, supercritical fluid processing and particle coating. The merits and limitations of these technologies are discussed with reference to their applications to specific drug and/or excipient materials. The regulatory requirements applicable to particulate inhalation products are also reviewed briefly.